TRIPOLI - Brigades aligned with Libya's UN-backed government said on Saturday they had captured Ghardabiya air base from Islamic State to the south of the militant group's stronghold of Sirte.Spokesman Mohamed al-Gasri said the capture of the base, about 20 km (12 miles) from the centre of Sirte, was strategically significant since it cut off supply routes for Islamic State and "trapped them further" within the city.Three fighters from the government-backed brigades were killed and around five wounded in Saturday's fighting, he said.The brigades, mainly made up from fighters from the western city of Misrata, have driven Islamic State back to the outskirts of Sirte from the west over the past three weeks. They counter-attacked after Islamic State had advanced towards Misrata in early May.To the east, a separate force that controls oil terminals and is also loyal to the UN-backed government captured two small towns from Islamic State earlier this week.Western states are hoping the UN-backed government, which arrived in Tripoli in March, can bring together Libya's competing factions to defeat Islamic State
